package com.telecom.restaurant.util;

import org.apache.commons.codec.binary.Base64;
import org.springframework.util.DigestUtils;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * Created by qiqi on 2019/12/2.
 */
public class EncryptUtil {

    private static final String key = "telecom_restaurant_manage"; // 加密秘钥

    private static final String KEY_ALGORITHM = "DESede";
    private static final String DEFAULT_CIPHER_ALGORITHM = "DESede/ECB/PKCS5Padding";// 默认的加密算法

    private static Cipher encrypt_cipher = null;
    private static Cipher decrypt_cipher = null;

    static {
        try {
            SecretKeySpec secretKey = getSecretKey(key);
            // 创建加密器
            encrypt_cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
            encrypt_cipher.init(Cipher.ENCRYPT_MODE, secretKey);

            // 创建解密器
            decrypt_cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
            decrypt_cipher.init(Cipher.DECRYPT_MODE, secretKey);

        } catch (Exception ex) {
            ex.printStackTrace();
        }

    }

    public static void main(String[] args) {

        String encrypt = encrypt("test"); // DUIBN7LTi2I=

        System.out.println(encrypt);

        encrypt = "3zBZ6DorA3Q=";

        System.out.println(decrypt(encrypt));
    }

    /**
     * DESede 加密操作
     *
     * @param content 待加密内容
     * @return 返回Base64转码后的加密数据
     */
    public static String encrypt(String content) {
        try {
            byte[] byteContent = content.getBytes("utf-8");
            synchronized (encrypt_cipher) {
                byte[] result = encrypt_cipher.doFinal(byteContent);// 加密
                return Base64.encodeBase64String(result);// 通过Base64转码返回
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }

    /**
     * } } DESede 解密操作
     *
     * @param content
     * @return
     */
    public static String decrypt(String content) {
        try {
            synchronized (decrypt_cipher) {
                byte[] result = decrypt_cipher.doFinal(Base64.decodeBase64(content));
                return new String(result, "utf-8");
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return null;
    }

    /**
     * }
     * 生成加密秘钥
     *
     * @return
     */
    private static SecretKeySpec getSecretKey(final String key) {
        //返回生成指定算法密钥生成器的KeyGenerator 对象
        KeyGenerator kg = null;
        try {
            kg = KeyGenerator.getInstance(KEY_ALGORITHM);
            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
            random.setSeed(key.getBytes());
            kg.init(112, random);

            //生成一个密钥
            SecretKey secretKey = kg.generateKey();
            return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);
            // 转换为DESede专用密钥
        } catch (NoSuchAlgorithmException ex) {
            ex.printStackTrace();
        }
        return null;
    }

    public static String md5(String str) {

        String base = str + key;

        String md5 = DigestUtils.md5DigestAsHex(base.getBytes());

        return md5;
    }

}
